1. Field of the Invention
The present invention relates to an electronic percussion instrument such as electronic drum and electronic cymbal.
2. Description of the Related Art
Electronic cymbal sounds are generates by striking the instrument with a drumstick and converting the resulting vibrations produced in the instrument body to electrical signals and outputting the sounds through a speaker or headphone, as disclosed in a Japanese Practical Utility Model H4-3358, for example.
The performance capabilities demanded of such electronic cymbal instruments include: (1) response characteristics should be uniform regardless of the strike point; (2) vibrations generated by the strike should diminish smoothly without exhibiting the so-called "violent decay" phenomenon; (3) the impact sound generated by the drumstick should be low. For such reasons, cymbals are mostly made of a plastic plates of about 5 mm thickness molded into a flat plate or, as in non-electronic cymbal instruments, into a convex front surface. Also, to lower the impact sound, a padding made of such materials as rubber is attached to the strike region of the instrument, and, sensors such as piezo-electric elements are attached to the back side of the cymbal to convert the mechanical vibrations to electrical signals.
To enable performing rim shot playing (normal playing) and cup playing as do non-electronic cymbal instruments, the electronic cymbals are provided with a rim section and a pad section such that normal playing sounds are produced by striking the rim section while cup sounds are produced by rapping the pad section.
FIGS. 2-4 show various view of a conventional electronic cymbal instrument where FIG. 2 is a plan view, FIG. 3 is an enlarged cross sectional view of essential parts, and FIG. 4 is a cross sectional view of a rim switch. This cymbal instrument 1 is comprised by a dish-shaped instrument body 2 having an upward opening, a membrane 3 covering the upper opening section of the instrument body 2, a transducer 4 to convert the vibrations generated in the pad section A to electrical signals and a rim switch 5 to generate normal sounds when the rim section B is stricken.
The membrane 3 is comprised by a circular vibrational strip 6 (made of a metal, wood or plastic resin) and a pad 7 (made of a such flexible material as butyl rubber) for covering the front surface of the vibrational strip 6 and the rim switch 5. The central region of the instrument constitutes the pad section A and the outer peripheral region constitutes the rim section B. The transducer 4 is attached to the back surface of the vibrational strip 6.
As shown in a detailed view in FIG. 4, the rim switch 5 is comprised by two proximally disposed opposing flexible sheets 8A, 8B, a spacer 9 disposed between the sheets 8A, 8B, and a set of contacts consisting of a fixed point 10 and a movable point 11 respectively disposed on the opposing sheets 8A, 8B. The rim switch 5 is firmly attached to the front surface of the membrane attachment section 12 provided throughout the outer periphery of the instrument body 2, and is covered over by the outer periphery of the pad 7.
Pad 7 is a circular shaped member having a diameter larger than that of the vibrational strip 6, and its outer periphery constitutes the covering section 7A for folding over the rim switch 5. The front surface of the covering section 7A, which is formed into a convex front surface, clearly divides the pad section A from the rim section B. On the back surface side of the covering section 7A, there are provided a switch compression section 13 comprised by a ring-shaped protrusion and two ringshaped grooves 14. The pressing surface 13a of the switch compression section 13 for pressing onto the rim switch 5 is shaped flat.
A fold-back section 16 folding over to the back surface of the instrument extends integrally all around the outer periphery of the covering section 7A, thereby forming a ring-shaped groove 17 between the fold-back section 16 and the covering section 7A. The groove 17 is coupled to the membrane attachment section 12 and is firmly fixed thereto with an adhesive.
The electronic cymbal instrument 1 having the construction presented above is normally played by rapping the pad section A with a drumstick, and when it is desired to switch the playing mode, the rim section B is hit. When the rim section B is hit, the covering section 7A of the pad 7 undergoes elastic deformation, and the switch compression section 13 presses down on the upper sheet 8B, which causes the movable point 11 to touch the fixed point 10 to activate the rim switch 5 to produce rim shot sounds.
In such a conventional electronic cymbal instrument 1, the switch compression section 13 (for pressing on the rim switch 5) is provided on the back surface of the covering section 7A which covers over the rim switch 5 so that the magnitude of a stroke necessary to activate the rim switch 5 corresponds to the amount of elastic deformation produced by the switch compression section 13 in respond to the striking action of the drumstick. However, a problem with such a design is that, because the pressing surface 13a of the switch compression section 13 is flat, it is sometimes difficult to activate the rim switch 5 depending on the striking direction of the drumstick.
In other words, a vertical hit will produce a sufficient stroke in the switch compression section 13 to activate the rim switch 5, but any hit from a slant or horizontal direction may not produced sufficient stroke because of a dispersion of the striking force resulting that the rim switch 5 cannot be activated.